While I'm not suggesting you abandon the idea of supplementing for B12, both Marmite and nutritional yeast are tasty and happen to be good sources of B12 at the same time, though, I would eat them even if they weren't. You will also find a lot of cereal is fortified with B12. Precisely because it's so important.
– David SJan 31 '17 at 20:25

1

@DavidS Nutritional yeast is not a source of B12! Unless it's fortified, obviously, and sometimes it is. I heard if you produce the yeast yourself, there would usually be some bacteria which make B12, but the industrial kinds of yeast don't produce any B12.
– NobodyJan 7 '18 at 21:23

@Nobody I don't think saying it's not a source is any clearer than me saying it is, since many a vegan cupboard will have nutritional yeast in it specifically for the B12. However, if you're saying a fortified food should not be considered reliable 'source' (in that it is not the whole-food source of the nutrient) then I completely agree with you.
– David SJan 8 '18 at 13:25

@DavidS Saying it's not a source means no one will buy nutritional yeast, eat it for the B12, for years, become ill because of lack of B12, and then suddenly notice that it didn't contain B12 after all. Saying that nutritional yeast contains B12 is like saying soy "milk" contains B12 - it's wrong. That both products exist in variants fortified with B12 doesn't change anything about that, because not all of them are fortified. The nutritional yeast in my pantry for example doesn't contain B12, because I wasn't paying attention when buying it. I noticed only months later.
– NobodyJan 8 '18 at 13:39

1

@DavidS I was talking about sensible wording, not about the underlying facts. I think we agree about the hard facts.
– NobodyJan 8 '18 at 15:57

5 Answers
5

No. B12 is an extremely important vitamin supporting many bodily and psychiatric functions. Fun fact (and I need citation here) is that it is so important you can live without it for months, exactly because your liver caches it in case you don't intake any for a while.

How can I obtain this vitamin as a vegan?

With a supplement. Ignore percent daily value in IU, it is a very misleading and bogus metric. 1000µg a day is what I take per advice from my doctor.

Without a supplement as a vegan, you will become deficient, but you may not feel the effects for over a year. And they are subtle effects more like your health randomly deteriorating.

I agree that the RDA is a vast underestimate for B12 but 50μg should be enough to maintain B12 stores unless you are severely deficient.
– Tom KellyFeb 5 '17 at 0:33

Just came across this and wanted to clarify one small issue. B12 is normally absorbed in conjuction with intrinsic factor - ncbi.nlm.nih.gov/pubmed/1775933 , however, it can also be passively absorbed without intrinsic factor - veganhealth.org/b12/dig , however passive absorption is less efficient. In people with "normal" digestive tracts require perhaps 50 mcg or less. In people without intrinsic factor or illness of the terminal ileum they need higher amounts perhaps 1,000 mcg. When in doubt, if you take supplements, take 1,000 mcg supplements.
– PantherSep 6 '17 at 18:49

1

It may be worth mentioning that some mushrooms contain Vitamin B12. Consumption of 50 g of dried shiitake mushrooms per day, for instance, is sufficient to meet RDA for B12 intake. (source: ncbi.nlm.nih.gov/pmc/articles/PMC4042564)
– user977Sep 13 '17 at 5:18

@aduckinthewinter my doctor instructs me to take about 50 times the RDA, and when I was taking the RDA I was very deficient. IMO it would be better to not have an RDA than a wrong one.
– djechlinSep 14 '17 at 2:08

Yes and maybe your doctor gave you advice which applies to you, and not everyone. If my doctor tells me I have cancer and should get chemo-therapy I won't tell everyone that my doctor told me to get chemo-therapy so they should, too. :P (compare comment by @Panther)
– NobodyJan 8 '18 at 13:42

B12 deficiency may have more than one cause, regardless of being a vegetarian or not:

low level of B12 in the food

an infection with a parasite

pernicious anemia

So, before starting taking large amounts of B12, you should discuss with a nutritionist or a medical doctor. Although, there is not a clear upper limit for B12 daily intake, higher doses intake should be avoided, if not really necessary (source), especially when some diseases are present.

Anyway, as a vegetarian, one should make sure that Vitamim B12 Test is included in periodical blood testing.

"periodical blood testing"? Which planet do you live on? I might need to move. I haven't seen a doctor in at least 5 years and I wouldn't expect most of the world's population to visit one much more often when they aren't obviously ill.
– NobodyJan 7 '18 at 21:27

@Nobody - I don't think what "most of the world's population" does is very relevant here. Periodical blood testing (e.g. yearly) is medically recommended because it can provide signs of certain diseases. Most if not all the serious companies in the area I work in provide private health insurance plans that cover the very basic blood tests once per year. While being a vegetarian is perfectly fine, it also incurs some risks (i.e. deficits) that should be regularly checked for).
– AlexeiJan 7 '18 at 21:38

I think it's relevant that the majority of the world's population has more pressing things to spend money on, like food. Also I'm pretty sure my $300+/month plan wouldn't include something like this even if I had already reached the deductibles cap for that year (something I have thankfully never managed before).
– NobodyJan 7 '18 at 21:43

There are a lot of different "milks" that are fortified with B12. Many brands of almond milk or coconut milk contain it. Ironically if you are over fifty (like me) and get you B12 through fortified milks and supplements you are probably less likely to suffer from B12 deficiencies than most carnivores, because as you get older your body does not break down natural sources of B12 as easily. The fortified almond milk and supplements are a better source than meat.

It is widely and highly recommended to take daily B12 supplements to support a healthy and varied vegan diet, because B12 is essential and cannot be produced by the human body.

By the way, a bit off-topic, but I have read and heard that before our modern life, it would be easier to get B12 just by living a vegan natural lifestyle, as we would get traces of it from the soil or rivers. But our excessive use of chemicals sprayed on food and put on water, means that we have less of the bacteria that produce these rare vitamins. I don't have any references on this, so don't take my word for it.

Regarding plant sources, this page seems to contain well-researched information: http://veganhealth.org/b12/plant. The reason I recommend this article is because some plant-based products report the presence of B12, but my understanding is that absorption but the body cannot be guaranteed.

Inactive B12 analogues in plant foods compromise the accuracy of
traditional methods used to determine the vitamin B12 amounts and
activity of a food. Bacterial contamination of a food can create the
false impression that all such foods contain B12 analogues. The only
reliable way to determine if a food is a source of active B12 is to
test various batches of that food to see if it reduces methyl malonic
acid (MMA) levels in humans.

As an example, I have a packet of Spirulina that shows in the nutritional information that it contains 170 micrograms of B12 (6800 %NRV) per 100g (the whole packet). And a packet of Chlorella shows 220 micrograms per 100g (8800% RI).

But I still cannot recommend people to rely on these sources after reading a bit from that site. I don't have a medical or nutrition background, and I have not read all of it, so I can't make any conclusions.

I'd say, to be on the safe side, take supplements. There are fortified foods, but I can't be sure that I will have them daily so I use B12 liquid which actually tastes good. I can't stand tablets. That just takes a drop under the tongue.

That said, both Spirula and Chrorella have excellent reputation as "superfoods" which are also very rich in protein, so I suppose it's good to include them in a vegan diet anyway, but not as a sole source of B12, for the reasons mentioned above.

Hopefully, the world will go vegan soon and we'll have more research into this area. Or perhaps because of the environmental benefits of the plant-based diet, nature will return to its pristine form and we'll get it effortlessly. Until then, let's take our B12 :).

Welcome to Vegetarianism StackExchange. :) In general, answers that just point to a link in order to answer the question are not really a good fit for the format here. Of course you can (and should) use references in your answers, but rather than just simply pointing to a link, you can extract information from the website you point to and compile it, in order to answer, on your own, the question from the OP. One of the problems with link answers is that links get broken over time. Another one is that you can just Google that on your own. Thre should be some added value that you provide.
– Alexander RossaJul 15 '17 at 7:40

This is certainly a myth that vegetarians can't live without supplements particularly vitamin B12. In India people have been leaving for ages without any known symptoms of B12 deficiency since they consume milk everyday raw or as tea majorly.

You will see the cow is given much prominence due to this. It's milk is lighter, has more bio-available B12. Also it contains many other essential vitamins and minerals required for proper human growth.